Firearms currently in use for example by special forces around the world function as follows. When a cartridge is fired, the recoil or the gas pressure retracts the slide—also called the breech block or the locking piece. The extractor (also called an extractor claw) that is attached to the slide extracts the empty casing from the breech by a groove intended for this purpose.
During further rearward travel the empty casing held by the retractor strikes the ejector that is typically attached to the grip of the pistol. As a result, the casing is usually ejected laterally upward through the ejection window of the slide, while the slide continues to travel rearward and cocks any striker piece present there or a firing pin (also called a hammer or cocking means), thereby creating readiness to fire.
Once it has reached its rear retracted position the recoil spring (also called a closing spring or feed spring) then returns the slide forward. The slide at the same time feeds a new cartridge from the magazine to the breech. Once in the forward closed position, the new cartridge is in the breech, and the striker piece or firing pin is cocked and the weapon ready to fire. The shooter then only has to release and then pull the trigger for the next shot.
Once the magazine has been emptied by firing the weapon, the follower presses on the slide catch lever that engages a corresponding cutout of the slide and holds the slide in place in the rear retracted position. After the magazine has been changed, the slide catch lever must be unlocked often by exerting a strong amount of force, the slide catch lever being under a relatively high load applied by the recoil spring. This procedure can become a difficult task with gloves, sweaty hands, or the tremendous stress in an active situation, and this difficulty can in the worst case result in the death of the force team member.
Various approaches currently exist that are intended to facilitate or attempt to circumvent this high-force unlocking procedure. Raised areas—known as thumb rests or textures—are provided, for example, on the slide catch lever in order to increase friction and thus prevent a finger from sliding off during the unlocking procedure. The manipulation technique known as the “double hand release” tries to address this problem whereby the slide catch lever is operated by the thumb of the other hand since this enables more pressure to be applied to the slide catch lever.
Another possible approach consists in modifying the manipulation of the weapon in order to unlock the slide after insertion of a new magazine and to circumvent operating the slide catch lever—for example, the so-called “overhand release” or “sling shot” in which the slide is moved by the other hand manually further rearward into the retracted position so as to reduce pressure on the slide catch lever, as a result of which this lever is moved by the return spring back to the release position.
However the previous procedures demand comprehensive training of the user in order to be able to perform “blindly” in an emergency situation. This cannot be assumed for a force team member for whom there is a high probability that he/she was never previously involved in an exchange of gunfire.